Method of making molds



(No Model.) 2 sheets-sheet 1.

4 H. D. BUGHMAN.

METHOD OF MAKING MOLDS.

Patented Aug. 12-

, (No Model.) 2 Sheets-Sheet 2.

H. D. BUCHMAN.

METHOD OF MAKING MOLDS. No. 434,104. Patented Aug. 12, 1890.

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UNITED STATES PATENT OFFICE.

HENRY D. BUCHMAN, OF ALLEGHENY, PENNSYLVANIA.

METHOD OF MAKING MOLDS.

SPECIFICATION forming part of Letters Patent No. 434,104, dated August 12, 1890.

Application filed May 7, 1890. Serial No. 350,929. (No model) invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon,which form a part of this specification.

My invention relates to founding, and especially to the preparation of molded molds.

In casting articles containing a number of apertures it is frequently a matter of considerable expense, both of time and labor, to make the cores required to produce these apertures and to place them accurately in position in the mold. In the case of cast-iron .flanges for metallic pipe a large number of holes must be formed in the flange for the bolts or rivets that unite it to the pipe and to the next flange, and these holes must be all of the same diameter in each and every flange, and since sand cores are destroyed when the casting is removed from the mold it becomes a costly and tedious job to make the great quantity required and to have them all of the same size. My invention is designed to facilitate the molding of such flanges, insuring the accuracy of the rivetholes both as to position and size, and providing for the rapid duplication of flanges precisely alike in this particular. I accomplish this by the use of the indestructible metallic cores hereinafter described and by my improved method of molding.

In the drawings, Figure 1 is a vertical section of the flask. Fig. 2 is a plan View of the same, partly broken away. Figs. 3 and 4 show my improved metallic core for the rivetholes. Fig. 5 is a view of the pattern, partly in section. Figs. 6 to 11 illustrate my method of molding, and Fig. 12 is a View of a portion of a pipe and flange.

My method is applicable to many kinds of articles; but I will describe it as applied to the production of the flange shown in Fig. 12, which is L-shaped in-cross-section and is pro vided with a number of rivet or bolt holes in both the face and neck of the flange, the

former being that which meets the flange on the adjoining section of pipe and the latter that which is riveted to the pipe. The pat-' tern A that I use is shown in Fig. 5. It is composed of two parts a a, which separate along a line coinciding with the diameters of the holes a I use a three-part flask composed of a cope B, a check 0 O, and a drag D. They may be of any suitable shape, but are preferably annular. The cope and drag each consist of an outer and an inner ring or wall united by radial cross-bars b d. The check consists of an outer ring 0, having radialarms 0, projecting inwardly. The arms are cut away on the lower and inner sides, thereby forming inverted-L-shaped pieces. The inner wall 0 of the cheek is provided with outwardly-proj ecting short radial arms 0. The several parts of the flask have the usual ears and steady-pins, as shown. The check and cope are also provided with clamping-lugs b c for the clamps l3, and all three parts of the flask have diametrically-opposite trunnions, as 11 by which they'can be suspended and turned over when necessary.

The cores that I use for coring the holes in the face of the flange may be of sand, or they may be the same as the one I have invented for coring the holes in the neck of the flange. This is shown in Figs. 3 and 4:. It consists of a tube E,of metal or other suitable material, smeared with'shellac or other cement and rolled in sand, so as to have a thin coating e of sand adhering to it. The tubes should be strong enough to withstand the pressure of the sand in the mold when rammed and also the Weight of the molten iron when poured.

My method of forming the mold is as fol lows, referring to Figs. 6, 7, 8, 9, 10, and 11: The drag is first rammed up and the cores E for the face of the flange are set in suitable core-prints. (See Fig. 6.) The lower part a of the pattern is then laid on the pattern plate F, and the two portions of the check 0 C are placed one outside and the other inside of it. The cores E are then laid in the holes 03, and the upper part of the pattern a is closed down upon them. The check is then filled with sand and rammed up, as usual, the

depth of the cheek being such that the top and bottom of the pattern lie flush with the surface of the sand, the cores E being buried in the mold, as shown in Fig. 7. A layer of parting-sand is now spread upon the top of the cheek, and the cope is then placed in position and rammed up, as shown in Fig. 8. It is then removed and set aside temporarily. The upper part a of the pattern is then lifted out. (See Fig. 9.) The cope is now replaced on the cheek, and thertwo are clamped together. They are theninverted, and the lower portion a of the pattern is drawn out, leaving the cores E in position in the sand, as shown in Fig. 10. The cope and cheek are then turned over again to theirnormal position and placed upon the drag D. The mold is then finished in the usual manner, and is ready for pouring.

The heat of the molten metal tends to expand the metallic cores E; but this tendency is expended in contracting the internal bore, leaving the outer diameter unchanged. This is a feature of special importance, since a solid metallic core would increase slightly in size with each pouring, until its value as a gage for the rivet-holes would be entirely destroyed. I am able, however, to use my hollow cores an indefinite number of times with the certainty that the rivet-holes will always be of the same size and conform accurately to gage.

WVhen the mold is broken up, the metallic cores can be easily extracted from the casting, since their thin coating of sand gives them clearance enough for this without impairing their accuracy as gages. They can be quickly made ready for use again by simply coating them anew with sand. By the use of these cores and by my method of molding, in which the cores are rammed up in the mold with the pattern, which is then drawn out without disturbing the cores, I am able to produce large quantities of pipe-flanges or other castings to which this method is applicable at far less cost and with much greater accuracy than by anyother means known to me.

In case the cores are made of a material that does not tend to expand under the in tinence of heat, they may be solid instead of tubular.

Having thus described my invention, what .even with the outer faces of the pattern, and

withdrawing the parts of the pattern, leaving the cores undisturbed, substantially as described.

3. The method of molding which consists in preparing the drag, placing a two-part pattern in the check, with the cores held between the two parts, ramming up the check so that the surface of the sand is flush with the top and bottom of the pattern, makinga parting, placing the cope upon the cheek and ramming it up, then removing the cope, withdrawing one part of the pattern, replacing the cope,

withdrawing the other part of the pattern,

leaving the cores undisturbed, and then placing the cope and cheek upon the drag, substantially as described.

4. The method of making 'L-shaped pipeflanges having cored rivet-holes, as hereinbe fore described, consisting in forming a drag, placing cores therein for theholes in the face of the flange, placing in a check a two-part pattern, separable along the line of a series of holes corresponding with those in the neck of the flange, placingbetween theparts of the pattern a series of indestructible metallic sandcoated cores, ramming up the cheek and cope, withdrawing the two parts of the pattern without disturbing the cores, placing the cheek and cope on the drag, and finishing and pouring as usual, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

HENRY D. BUCI-IMAN.

lVitnesses:

HARRY S. BEAVER, CHARLES W'. TOWNSEND. 

